Why wont the paint stick to plaster????

urbancookie1

Thankyou all so much for your reply's.

Had a look at the state of it this morning and i still looks like i'll have to scrape some more off as it looks ok but if you rub the edge it peel's away.

Seams as if there a bit of a divide about the pva/waterd dowm emulsion subject.

Im going to go with the watered down emulsion remedy after ive done this scraping,(any ideas to make scraping easier?)

Oh, BTW its been plastered for about 5-6 weeks although its the bathroom and the shower is on at least twice a day it should be dry.

:beer:

Pretani

Two things come to mind urbancookie1. Either your plaster hasn't fully dried out because you are still using the shower or it's the paint. I recently painted a bedroom with emulsion and I had the same type of peeling you mentioned. The paint seemed to have a pva base. Test the paint out on a different room, it might be the paint.

want2bmortgage3

If the plaster has gone a lighter colour (it should have started dark and gradually patches lightened) then its dry enough to paint. You must though paint with either: cheap matt emulsion watered down about 50/50 OR 'paint for new plaster' available in most diy stores.
do this for the first coat, then use a better quality paint for the 2nd and 3rd coats in the colour you want the room.

Poppycat

We painted our hallway which was replastered with cheap B&Q budget paint (watered down) it dried with 5 minutes at most. Then we used Dulux emulsion after that with a brush

Only time we used pva was to allow plaster to adhere to the old ceiling as it had some gloss paint (just a little bit in places and some other awful stuff) Plaster told us to do that, we did two coats

We did us pva (watered down) on rendering outside in places like window sills and loose bits (cracks) and allowed the Dulux weathershiled to stick. Thats fine bee on on there now for over 15 months

paullwill8

Ideally you need to get the ceiling back to the plaster. Then get yourself down to your nearest Dulux Dec Centre and purchase Dulux supermatt. Unfortunately only avaliable in 10 ltr tubs but is on special at the moment.
DO NOT USE PVA PERIOD!
Once your ceiling is back to the plaster and dust free, mix your supermatt with water, approx 30% water to the first coat, then a 20% water mix for your 2nd coat, then you are ready to paint as normal.
The reason you should use supermatt ( or a non vinyl matt) is chemicals in the plaster can react with vinyl causing all sorts of probs.
You would probably be better top coating the ceiling in either a soft sheen or silk finish being a bathroom.
HTH.

misgrace

Good advice from Paulwillis, and dont use PVA as a seal coat, as the paint will sit on top of the PVA and not soak into the plaster, therefore any coats will sit on top of the PVA, and the paint will peel off, or bubble, or any number of things.

Get as much paint off as you can, any paint you cant get off, sand like mad, then, do your first coat (mistcoat), of a matt paint, not silk, or bathroom/kitchen paint.

Water it down, about 30-40%, it doesnt matter if it too Watery/thin, as long it covers the plaster, this will get into the plaster, and seal.

Then when you do your proper first coat,thin down again by about 15%, then your proper second coat about 5-10%, your better off doing an extra thinner coat, as you will see the difference in the finish, it will be much smoother, flatter, and look more proffessional.

You can do any finish you want, ie silk, or bathroom paint, after you have done your mistcoat/sealcoat/basecoat of the matt.:D

Debt_Free_Chick

My two-penneth, FWIW

Agree not to use PVA as it simply sits on top of the plaster.

Agree to apply one or two coats of watered down emulsion as base (mist) coats. The reason being that new plaster is like a sponge - these two coats will be absorbed and you'll see very little finish for your money/time/effort.

BUT ..... this means that the finishing top-coats will be absorbed to a much lesser extent, so you use best quality paint to get the right finish and don't waste it on a base coat which the new plaster simply drinks up.

Have recently had to decorate six rooms of a newly plastered extension and this method produced excellent results in every room.

It's also important that you've allowed the plaster to completely dry out. You can't see this - you'll see the surface dry, but you can't see how dry the plaster is behind the surface, so leave it as long as you can bear. 6-8 weeks is ideal, but others get away with 4-6 weeks.

My concern would be the bathroom. If it's being used daily, then you must make sure it's always well ventilated to assist the drying out. Ideally, heated too, but only with adequate ventilation to prevent condensation!

Lucy_DIY

Hello. I have recently modernised my Victorian property and had old walls replastered. Last weekend I had a decorator in to paint the bathroom walls (a good 4 weeks after plastering). One bathroom wall had had old wallpaper on, and the other three tiles. The decorator used 1 coat of white wash under 2 coats of Dulux bathroom paint. As the decorator was painting the second Dulux coat onto the previously wallpapered wall the new plaster started to fall away. This wall is now an eyesore. I am convinced this is the fault of the plasterer not cleaning the old wall. Our builders are blaming it on the decorator painting 2 coats of bathroom paint in one day. This doesn't seem right to me, but I am not an expert. Expert opinions most gratefully received!

chiefgoobster

Lucy DIY

so is the plaster falling off the top (skim) coat of the wall ...or is the whole lot coming away (ie down to bare brick ) ?

has any water / lots of moisture got behind this new wall ?

Nowt wrong with painting 2 coats in one day. Just depends on how long you leave it between coats.

Leif

The paint tin will tell you how long between coats, Dulux emulsion is typically 5 hours. But even if you coat too soon, all that will happen is the paint might not stay on properly, or it might crack, it won't pull the plaster off. From your post, the plaster was on top of wall paper, and now the plaster has come off, presumably with the old wall paper. To be honest wall paper can be only loosely attached. I pulled mine off one wall at a time! I would have thought the wallpaper should have been removed, not exactly a hard job is it?